Women who currently smoke tobacco face a significantly higher risk of infertility than non-smokers, while men who smoke may also experience problems affecting their ability to father children, the World Health Organisation (WHO) has warned.
In a new knowledge summary examining the relationship between tobacco use and fertility, the global health agency said decades of research had established a link between smoking and reproductive health problems in both sexes.
According to the publication, a systematic review of studies conducted between 2000 and 2026 found that women who currently smoked had a 40 per cent higher risk of infertility than women who did not smoke.
The review also found that women who had previously smoked but had quit had a 25 per cent lower risk of infertility compared with women who continued to smoke.
The findings, WHO said, point to the potential benefits of quitting tobacco for people seeking to protect or improve their reproductive health.
Infertility is defined as the inability to achieve pregnancy after 12 months or more of regular unprotected sexual intercourse. WHO estimates that one in six people of reproductive age worldwide experience infertility at some point in their lives.
Men also face reproductive risks
The WHO stressed that infertility should not be viewed exclusively as a women's health problem, pointing to evidence that tobacco use can adversely affect male reproductive and sexual health.
The organisation cited a recent review of 44 studies involving more than 60,000 men, which found an association between smoking and reproductive dysfunction.
The evidence linked tobacco smoking to semen abnormalities and sexual problems, including erectile dysfunction and difficulties with ejaculation.
Smoking was also associated with the absence of sperm in semen, reduced sperm movement and abnormalities in sperm shape — factors that can affect male fertility.
Waterpipe smoking, commonly known as hookah or shisha, was similarly identified as a potential risk to male reproductive health.
Smoking may affect fertility treatment
The WHO publication further warned that tobacco use could reduce the chances of achieving a successful pregnancy through assisted reproductive technologies.
It cited earlier research involving 21 studies which found that cigarette smoking was associated with fewer pregnancies and live births following fertility treatments, including in-vitro fertilisation (IVF).
According to the evidence reviewed, cigarette smoking could roughly halve the likelihood of successful outcomes from some fertility treatments.
The finding is particularly significant for couples who already require assisted reproductive care, as tobacco use may add another potentially modifiable factor to the challenges they face in achieving pregnancy.
Second-hand smoke also a concern
WHO also warned that people do not necessarily have to smoke themselves to potentially suffer reproductive health consequences.
Women exposed to second-hand tobacco smoke may face a higher risk of infertility and a lower likelihood of conceiving during each month they attempt pregnancy, the organisation said.
The warning broadens the reproductive-health implications of tobacco beyond individual smokers to partners, family members and others exposed to tobacco smoke.
However, WHO cautioned that evidence concerning newer tobacco and nicotine products remains less established.
Research on products such as e-cigarettes, waterpipes and smokeless tobacco is still developing, with the strongest body of evidence currently relating to conventional cigarette smoking.
The organisation said other tobacco and nicotine products could also pose fertility risks, but further research is needed to fully establish their effects.
WHO urges quitting support
Against the backdrop of widespread infertility, WHO urged healthcare providers to discuss the reproductive consequences of tobacco use with individuals and couples planning pregnancy.
It recommended that tobacco users be offered evidence-based assistance to quit and said brief advice on stopping tobacco use should be routinely provided across healthcare settings.
The agency said addressing tobacco use should form part of broader efforts to protect reproductive health, particularly given the significant number of people worldwide affected by infertility.
For couples planning to have children, the evidence provides another reason to address tobacco use early. Beyond its established links to major health conditions, smoking may also affect the ability to conceive, reproductive function and the outcome of fertility treatment.
WHO's message is therefore that tobacco cessation should not only be viewed as a measure to prevent chronic disease, but also as part of protecting reproductive health and improving the chances of a healthy pregnancy.